JP2020535323A - Lithium-ion battery recycling method - Google Patents

Abstract

A step of shredding a lithium ion battery and immersing the residue in an organic solvent; a step of supplying the shredded battery residue to a dryer to produce a gaseous organic phase and a dry battery residue; drying The step of supplying the battery residue to the magnetic separator to remove the magnetic particles; the step of crushing the non-magnetic battery residue; The step of leaching the slurry; the step of filtering the leachate to remove the non-leaky metal; the step of supplying the leachate to the sulfide precipitation tank; the step of neutralizing the leachate; the step of mixing the leachate with the organic extraction solvent; the solvent Separation of cobalt and manganese from leachate using extraction and electrolysis; Crystallization of sodium sulfate from aqueous phase; Addition of sodium carbonate to the solution and heating of sodium carbonate and solution to precipitate lithium carbonate A method of recycling a lithium ion battery is provided, which comprises a step of producing the lithium carbonate; [Selection diagram] Fig. 1

Description

[0001] A method of recycling a lithium ion battery is provided.

[0002] Today, most lithium-ion batteries have a significant environmental impact and are recycled in a way that makes it impossible to recover many valuable materials. Materials used in the manufacture of lithium-ion batteries, such as lithium and cobalt, are projected to be at risk in the near future, and alternative sources of these materials must be used to guarantee affordable prices for lithium-ion batteries. There is. In addition, the development of raw materials for battery components has a large environmental impact, so recycling is necessary to obtain a positive impact on the environment when using electric vehicles.

[0003] Some battery recyclers focus on the mechanical and physical separation of different battery components, such as casings, current collectors and electrode materials, after crushing. These processes usually involve crushing the battery in a controlled inert atmosphere. The crushed material is then separated by sieving, air separation and magnetic separation and sent to another facility for further processing. These types offer very little in terms of manufacturing value-added components and help counteract the environmental impact of handling the entire used battery primarily.

[0004] Pyrometallurgy can be used to separate different elements of used lithium-ion batteries. Combusting components by heating organics and polymers at high temperatures. Heavy metals such as cobalt, copper and nickel melt into alloys, while other elements become slag. Metal alloys are sold to metal smelters for separation. Importantly, lithium becomes a slag in these processes and is lost and cannot be recovered and sold. The alloys sold have a slight value of the separated pure metal.

[0005] Hydrometallurgical processes are often used to separate and purify the different metals contained in the cathode after mechanical treatment. These processes typically include a leaching step to dissolve the metal oxide in aqueous solution and various steps of precipitation and separation to obtain a relatively pure metal. These types of processes are still under development and are expensive to operate due to processes such as immersion in liquid nitrogen and the use of large amounts of chemicals. Also, usually, the treatment of waste liquid is hardly considered.

[0006] There is currently no large-scale industrial process capable of handling increasing amounts of used lithium ions. Even smaller pilot plants are still in the research and development stage and cannot process all of the different battery compositions to purify the value-added elements in an economical way.

[0007] Therefore, there is still a need to provide a method that can economically handle all types of used lithium-ion batteries.

[0008] According to the present disclosure, a lithium ion battery is shredded, the residue is immersed in an organic solvent to safely discharge the battery, and the shredded battery residue and organic compounds and lithium hexafluorophosphate are removed. A step of producing a liquid containing; a step of supplying shredded battery residue to a dryer to produce a gaseous organic phase and a dry battery residue; a magnetic battery residue and a non-magnetic battery residue. A step of feeding the dry battery residue containing the above to a magnetic separator to remove magnetic particles from the dry battery residue; the non-magnetic battery residue is crushed to a particle size of about 0.1-10 mm. A step of producing a particle size distribution that includes an upper limit range containing plastic and an intermediate and lower limit range of fine particles containing aluminum, copper, metal and graphite; the fine particles and acid are mixed to produce a slurry to produce a metal oxide. The step of leaching the slurry to produce a leachate containing a metal sulfate and a non-leaky material; the step of filtering the leachate to remove the non-leaky material from the leachate; and feeding the leachate to a sulfide precipitation tank. To remove ionic copper impurities from the leachate; to neutralize the leachate to pH 3.5-5 to remove residual iron and aluminum from the leachate; to mix the leachate with an organic extraction solvent. To produce an aqueous phase containing lithium, sodium, and nickel and an organic phase containing cobalt, manganese, and residual nickel; crystallizing sodium sulfate from the aqueous phase containing lithium to form lithium and sulfuric acid. A step of producing a liquid containing sodium crystals; a step of adding sodium carbonate to the liquid and heating the sodium carbonate and the liquid to form a precipitate of lithium carbonate; and a step of drying and recovering the lithium carbonate. A method of recycling lithium ion batteries, including, is provided.

[0009] In one embodiment, the organic solvent is an aliphatic carbonate.
[0010] In a further embodiment, the organic solvent is kept at a temperature below 40 ° C.
[0011] In an additional embodiment, the lithium ion battery is shredded to a particle size of about 5-10 millimeters in an inert atmosphere using, for example, nitrogen or CO ₂ , but not limited to these.

[0012] In another embodiment, the shredded battery residue is separated from the liquid by sieving or filtration.
[0013] In an additional embodiment, the method described herein further comprises the step of evaporating the liquid in an evaporator to produce a slurry and a condensate of light organic matter.

[0014] In another embodiment, the method described herein separates dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) and ethylene carbonate (EC) from the condensate of light organic matter. Including the process of

[0015] In one embodiment, the liquid is evaporated at a temperature of 90 ° C to 126 ° C.
[0016] In another embodiment, the slurry is burned at a temperature of about 500 ° C., to produce hydrofluoric acid (HF) and phosphorus pentoxide (P 2 _{O 5)} combustion gas containing.

[0017] In another embodiment, further to remove HF in a fluidized bed reactor, to neutralize the P ₂ O ₅ in the wet scrubber to form the sodium phosphate (Na 3 _{PO 4).}
[0018] In one embodiment, the shredded battery residue is dried at a temperature between 200 and 300 ° C.

[0019] In one embodiment, the non-magnetic battery residue is ground with a hammer mill or impact crusher.
[0020] In one embodiment, the method described herein further comprises the step of extracting aluminum and copper from the ground non-magnetic battery using an eddy current separator.

[0021] In another embodiment, aluminum and copper are further separated.
[0022] In one embodiment, the microparticles are mixed with sulfuric acid and water.
[0023] In a further embodiment, the microparticles and acid are mixed to produce a metal oxide slurry with a solid concentration between 75 and 125 kg of solid per cubic meter of acid solution.

[0024] In another embodiment, the method described herein further comprises adding a reducing agent to the metal oxide slurry for leaching.
[0025] In one embodiment, the reducing agent is at least one of hydrogen peroxide (H ₂ O ₂ ), manganese oxide (MnO ₂ ), aluminum powder (Al) and combinations thereof.

[0026] In another embodiment, the method described herein further comprises the step of purifying graphite from a non-exudative material in a furnace.
[0027] In one embodiment, the furnace is operating at a temperature of about 200-800 ° C.

[0028] In one embodiment, the method described herein further comprises the step of precipitating ionic copper impurities by precipitation with sulfide ions.
[0029] In a further embodiment, the method described herein further comprises the step of precipitating aluminum and iron impurities by increasing the pH of the aqueous solution.

[0030] In another embodiment, the method described herein further comprises mixing the leachate with an organic extraction solvent in a diluent.
[0031] In a further embodiment, the diluent is a petroleum-based reagent.

[0032] In one embodiment, the method described herein further comprises the step of scrubbing and stripping the organic phase to extract cobalt and manganese.
[0033] In another embodiment, cobalt and manganese are separated by electrowinning.

[0034] In an additional embodiment, the method described herein raises the pH of the aqueous phase to between 10 and 12 and removes nickel sulfate (NiSO ₄ ) from the aqueous phase to nickel hydroxide (NiSO ₄ ). It further includes a step of precipitating as Ni (OH) ₂ ).

[0035] In one embodiment, the aqueous phase is cooled at a temperature between about 0 ° C. and 10 ° C. prior to crystallization.
[0036] In another embodiment, the method described herein further comprises the step of electrolyzing sodium sulfate crystals to produce sulfuric acid and sodium hydroxide.

[0037] In one embodiment, carbonate ions are added to the liquid by supplying sodium carbonate or bubbling CO ₂ gas.
[0038] In a further embodiment, the lithium ion battery is a battery pack.

[0039] In another embodiment, the lithium ion battery is a vehicle battery.
[0040] Here, refer to the attached drawing.

[0041] The organic separation step of the method according to one embodiment, which is included in the present specification, is schematically shown. [0042] The electromechanical separation step of the method according to one embodiment, which is included herein, is schematically shown. [0043] The hydrometallurgical process of the method according to one embodiment, which is included in the present specification, is schematically shown. [0044] A plurality of metal separation steps included herein and after the solvent extraction step according to one embodiment are schematically shown.

[0045] Note that similar features are identified by similar reference numbers throughout the accompanying drawings.
[0046] According to the description of the present invention, there is provided a method for recycling a lithium ion battery.

[0047] In the present disclosure, a lithium ion battery is shredded, the residue is immersed in an organic solvent to safely discharge the battery, and the shredded battery residue and a liquid containing an organic compound and lithium hexafluorophosphate are contained. And; a step of supplying shredded battery residue to a dryer to produce a gaseous organic phase and a dry battery residue; including a magnetic battery residue and a non-magnetic battery residue. The step of feeding the dry battery residue to the magnetic separator to remove the magnetic particles from the dry battery residue; crushing the non-magnetic battery residue to the upper limit including plastic and aluminum, copper, metal and graphite. A step of producing a particle size distribution that includes an intermediate and lower limit range of the containing fine particles; the fine particles and the acid are mixed to form a slurry, and the metal oxide slurry is leached to obtain a metal sulfate and a non-leaky material. A step of producing a leachate containing; a step of filtering the leachate to remove a non-leaving material from the leachate; a step of supplying the leachate to a sulfide precipitation tank to remove ionic copper impurities from the leachate; A step of neutralizing the leachate to pH 3.5-5 to remove residual iron and aluminum from the leachate; mixing the leachate with an organic extraction solvent, an aqueous phase containing lithium, sodium, and nickel, and cobalt. , Manganese, and an organic phase containing residual nickel; a step of crystallizing sodium sulfate from an aqueous phase containing lithium to produce a liquid containing lithium and sodium sulfate crystals; Provided is a method for recycling a lithium ion battery, which comprises a step of forming a precipitate of lithium carbonate by adding to and heating sodium carbonate and a liquid; and a step of drying and recovering lithium carbonate.

[0048] The method described herein is designed to handle all cathode compositions of lithium-ion batteries available on the market. The methods described herein can also be carried out in factories where all forms of battery packs, including plastic casings and supports, can also be processed to limit manual disassembly.

Used batteries that have reached the end of their life can have different compositions. The cathode is usually made of lithium metal oxide, and the metal part is made of a mixture of cobalt, nickel, and manganese. Other cathode compositions such as lithium iron phosphate can also be processed. The anode is often made of graphite, but can also be made of metallic lithium. The electrolyte can be either a liquid solvent, usually a mixture of aliphatic carbonates and cyclic carbonates and a dissolved lithium salt, or a solid, eg, a lithium-based solid electrolyte.
Organic separation
[0050] As is apparent from FIG. 1, this method is the first step of shredding the received 1 used battery 2 and safely discharging the internal components of the battery and exposing it to the downstream electrolyte extract. including. In one embodiment, shredding is performed to a target particle size of about 5-10 mm.

[0051] A used battery may have a charge remaining in it. When the internal components of a charged battery are exposed to the moisture contained in the ambient air, an exothermic reaction that produces hydrogen gas occurs. This poses a significant risk of burning hydrogen gas. To minimize the risk of burning, the entire used battery is shredded and then immersed in an organic solvent. This organic solvent is used to dissolve and extract an electrolyte salt contained in a battery, such as lithium hexafluorophosphate (LiPF ₆ ). It is miscible with the electrolyte solvent found in the battery cells, preferably aliphatic carbonates. Therefore, the contact between the internal components of the battery and oxygen is limited. Also, when an exothermic reaction occurs, the organic solvent acts as a heat sink, thus reducing operational hazards. In one embodiment, the organic solvent is kept below 40 ° C. by circulating the solvent through a heat exchanger or by a jacket around a container that receives shredded batteries.

[0052] Following shred 2, the particles or shredded battery residue, and solvent go through an extraction step, which ensures good cleaning of the electrolyte salt. The extractant is the same solvent used in shredding step 2. In one embodiment, the extraction is performed at a temperature between 40 ° C. and 60 ° C., the residence time is between 30 minutes and 1.5 hours, and the test operating point is 50 ° C. for 1 hour. This step can be performed in any common heating and mixing tank unit. The shredded battery residue or particles are then separated from the liquid by sieving or filtration.

The liquid phase containing the organic solvent is supplied to an evaporator 3 operating at the boiling point of the solvent mixture, which can vary from, for example, 90 ° C. of pure dimethyl carbonate to a maximum of 126 ° C. of pure diethyl carbonate. A typical operating point for a mixture of electrolyte salt and solvent is expected to be about 90 ° C. at atmospheric pressure. Lighter molecules in the organic phase, mainly the solvent used upstream, evaporate and condense. Heavier organic molecules, which still contain electrolyte salts from used batteries, remain as a slurry at the bottom of the evaporator.

[0054] Most of the condensate of light organic matter can be returned to shredding step 2, and the other part corresponding to the accumulation of organic solvent is separated step 4 to purify different molecules in the light organic phase. Outflow to. The light organic phase is composed of organic carbonate compounds such as, but not limited to, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate and ethylene carbonate. In one embodiment, three distillation columns are used. The first column 4a is operated at about 90 ° C. to obtain battery grade dimethyl carbonate (DMC) at column overhead. The bottom of the first column is supplied to the second column 4b. It contained ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC). The second column is operated at about 107 ° C. to obtain battery grade ethyl methyl carbonate (EMC) at column overhead. The bottom of the second column is fed to the third column 4c and operated at about 126 ° C., battery grade diethyl carbonate (DEC) at column overhead, and industrial grade ethylene carbonate (EC) from the bottom of the column. ).

[0055] Wet battery residue is fed to the dryer 7 operating between 200 and 300 ° C. to remove the organic solvent from the residue. The gas phase containing mainly light organic substances is sent to the outlet of the first solvent evaporation 3. The battery residue from the dryer outlet 7 is supplied to the magnetic separator 11.

[0056] The heavy organic slurry from the evaporator 3 is burned off at a temperature of about 500 ° C. 8 to eliminate toxic organic fluorophosphate molecules and remove all reactive fluoride compounds from the process. The combustion gases include hydrofluoric acid (HF) and phosphorus pentoxide (P ₂ O ₅ ); these molecules are highly reactive and need to be treated before being sent to the environment. HF is removed by dry scrubbers 9, such as, but not limited to, dry lime scrubbers or catalytic alumina dry scrubbers, where waste is safely removed at the aluminum plant as part of the supplied product. Can be processed. P ₂ O ₅ is neutralized with a wet scrubber 10 using a caustic solution to form environmentally harmless waste such as sodium phosphate (Na ₃ PO ₄ ).
Electromechanical separation
[0057] Battery residue is supplied to the magnetic separator 11 from the dryer outlet 7 in order to separate the iron pieces and particles lifted by the magnet from other solids.

The non-magnetic battery residue goes through the grinding step 12, i.e. reducing the average particle size to a smaller average particle size, between 0.1 and 2 millimeters. Different crushing and crushing unit operations can be used, such as, but not limited to, hammer mills or impact crushers. The plastic forms the upper limit of the particle size distribution. The aluminum foil and copper foil are crushed into a ribbon-like shape. The metal of the cathode and the graphite of the anode are ground to form the lower limit of the particle size distribution.

[0059] In one embodiment, the outlet from the crusher is then screened at about 1 millimeter 13. Fractions that are too large are fed to the second milling and sieving step 14 to allow the remaining anode and cathode materials attached to the aluminum and copper foils, such as, but not limited to, high shear mixers or. Remove using a device such as a cutting mill. After the second sieving of the same size (about 1 mm), the microparticles of step 14 are sent to mix with the microparticles from the previous sieving 13.

[0060] The coarse particles, mostly containing plastic, copper, and aluminum, are then fed to the eddy current separator 15, where the aluminum foil and copper foil are extracted. The remaining plastic can be sent to a recycling facility. Next, the aluminum foil and the copper foil are separated by density classification 16 using a device such as, but not limited to, an air classifier.
Hydrometallurgy
[0061] In the leaching tank 17, fine particles from the sieving unit are mixed with sulfuric acid and water to have an acidic mass concentration between 10% and 30% in the liquid phase of the slurry and about 17% acidic at the operating point. A metal oxide slurry having a mass concentration is obtained. For solid concentrations between 75 and 125 kg of solids per cubic meter of acid solution, mixing needs to be maintained near ambient temperature for 1-4 hours. A typical operation needs to be performed at a solid concentration of 100 kg / m ³ at about 20 ° C. for 3 hours.

[0062] A reducing agent to assist the leachate of transition metals, such as, but not limited to, hydrogen peroxide (H ₂ O ₂ ), manganese oxide (MnO ₂ ), or aluminum powder (Al), is also added to the reaction tank. It may be added. Typical working concentrations of the reducing agent are 0-30 w. Of the solution for H ₂ O ₂ . / W. %, In the case of MnO ₂ , 0 to 5 w. / W. % And Al, 0-5w. / W. Can fluctuate in%. The transition metals (Co, Ni, Mn) in the slurry are reduced or oxidized to a divalent (2+) oxidized state, which allows more leaching. Leaching of the metal oxide slurry produces a leachate of metal sulfate filtered from a solid non-leaching material.

[0063] As is apparent in FIG. 3, graphite and other non-exudative elements are filtered18 and sent to graphite purification. Sulfates containing lithium, cobalt, nickel, manganese, iron, aluminum, and copper as sulfates (Li ₂ SO ₄ , CoSO ₄ , NiSO ₄ , MnSO ₄ , Fe ₂ (SO) ₃ , Al ₂ (SO ₄ ) ₃ , CuSO ₄ ) is sent to the sulfide precipitate 21.

[0064] After filtration, the resulting graphite cake is suspended in a liquid similar to the aqueous solution from the leaching step 19. It also uses sulfuric acid and reducing agents such as, but not limited to, hydrogen peroxide (H ₂ O ₂ ), manganese oxide (Mn O ₂ ), or aluminum powder (Al), using the same composition as before. It is a mixture with. This solution solubilizes the metal remaining in graphite. The graphite is then filtered and washed thoroughly with water. The graphite cake is then fed to a furnace 20 operating at 200-800 ° C., preferably 600 ° C. to evaporate the remaining plastic and dry the graphite.

The leachate is sent to the sulfide precipitation tank 21 to remove the ionic copper in the solution obtained from the leachate metallic copper remaining after eddy current separation. Sulfide ion (S ^-) by binding to, copper impurities can be precipitated. The sulfide ion source can be any sulfide ionic compound such as, but not limited to, sodium sulfide (Na ₂ S) or bubbling hydrogen sulfide (H ₂ S). At pH less than 2 and temperatures between 40-80 ° C, the sulfide selectively binds to copper to form water-insoluble copper sulfide (CuS). Depending on the concentration of copper ions in the solution, the concentration of Na ₂ S will vary with Na ₂ S between the leached cell residue 1kg per 2～5Kg, retention time can be 30 minutes to 1 hour. The precipitate is filtered off the main process line and sold.
CuSO ₄ + Na ₂ S⇔CuS + Na ₂ SO ₄
The leachate was then neutralized to a pH between 3.5 and 5.0 by adding sodium hydroxide (NaOH) 22, precipitating the remaining iron and aluminum, insoluble in water. It forms hydroxide (Al (OH) ₃ , Fe (OH) ₃ ). Precipitation takes 30 minutes to 2 hours to stabilize and the expected reaction time is 1 hour. The precipitate is filtered from the process.
Al ₃ (SO ₄ ) ₂ + 6 NaOH ⇔ ₃ Al (OH) ₃ + 2Na ₂ SO ₄
NiSO ₄ + 2 NaOH ⇔ Ni (OH) ₂ + Na ₂ SO ₄
Final metal separation
[0067] The leachate is mixed with an organic extraction solvent (extractant) dissolved in a petroleum-based reagent (diluent) 23. The concentration of extractant in the diluent varies between 2-10 mass percentages, with more typical values between 4-6. When the pH of the aqueous solution is between 4.5 and 7, divalent transition metals (Co, Mn, Ni) are extracted by the organic phase, while lithium and sodium remain in the aqueous phase. Nickel is only partially extracted if the pH is kept between 5.4 and 6.2. This pH range is used to separate nickel from cobalt and manganese.

[0068] To carry out the solvent extraction process, a mixer settler, an extraction column such as a pulse column, a column for internal agitation using a rotary impeller, a reciprocating plate extraction column, a hollow fiber membrane and the like are used. May be good. In the case of the above equipment, the lighter organic phase is usually pumped from the top of the buffer zone (where the mixture is gone) and the heavier aqueous phase exits from the bottom of the equipment through another buffer zone. Decantation gives sufficient time to separate. The organic phase is then sent to the scrubbing and stripping steps and the aqueous phase (raffinate) is further sent to the precipitation step.

[0069] In the scrubbing step 24, the organic phase is brought into contact with an aqueous solution containing high concentrations of cobalt and manganese to selectively strip nickel from the organic phase. This scrubbing solution is part of a stripping solution rich in (Co, Mn) and its pH is adjusted between 3 and 4 with sodium hydroxide. The two phases are mixed and separated in a similar device as described above. The aqueous solution is returned and mixed with the solvent extraction inlet.

[0070] In stripping step 25, the organic phase is brought into contact with an aqueous solution containing sulfuric acid between pH 1 and 2 to strip cobalt and manganese together. Again, the two phases are mixed and separated using the same apparatus described above. Next, the washed organic solvent is fed back to the extraction step, and the currently (Co, Mn) -rich aqueous phase is divided between the scrubbing step 24 and the cobalt electrowinning step 26.

[0071] Cobalt and manganese must separate from each other. When neutralized with sodium hydroxide, they precipitate together, but because they have different standard reduction potentials (-0.28 V for cobalt, -1.18 V for manganese), they can be separated by electrowinning process 26. it can. Cobalt is plated on the cathode in the form of a metal and then scraped off. Manganese is oxidized to MnO ₂ and deposited on the anode. Cobalt electrowinning is performed using a non-split electrowinning cell with a cobalt blank cathode and DSA anode at a voltage of 2.7-5 V and a current density of 150-350 A / m ² . The electrolyte is supplied at a temperature between 45-70 ° C and a pH between 2.5-5. The used electrolyte is returned to the stripping step 25 as a stripping solution. The electrode reaction is shown as follows:
Cathode:
Co ²⁺ + 2e ⁻ ⇔ Co (s)
2H ⁺ + 2e ⁻ ⇔ H ₂
anode:

^{_{MnO 2 (s) + 2e -}} + 4H + ⇔Mn 2+ + 2H 2 O
[0072] After the solvent extraction step, the aqueous raffinate contains the majority of dissolved nickel sulphate (NiSO ₄ ). With the addition of sodium hydroxide, the pH of the solution rises between 10-12, the expected value is 10.8, 27, precipitating nickel hydroxide (Ni (OH) ₂ ). Precipitation takes 30 minutes to 2 hours to stabilize and the expected reaction time is 1 hour. Nickel hydroxide is filtered, washed, dried and sold 28.
NiSO ₄ + 2 NaOH ⇔ Ni (OH) ₂ + Na ₂ SO ₄
[0073] At this point in the process, the remaining aqueous solution contains a large proportion of sodium sulphate (Na ₂ SO ₄ ). Sodium sulfate is produced by the neutralization of sulfuric acid by sodium hydroxide that occurs during hydroxide precipitation. High concentrations of sodium sulphate are suitable for surface-cooled crystallization 29, coupled with the large dependence of its solubility on temperature. When the neutralized leachate is cooled between 0 ° C and 10 ° C, most of the sodium sulfate crystallizes into periohydrate crystals known as glauber salts (Na ₂ SO ₄ * 10H ₂ O). Removing sodium sulfate as hydrated crystals also has the advantage of concentrating the lithium remaining in the aqueous solution (mother solution). The produced crystals are fed to a centrifuge, dehydrated and washed.
_{Na 2 SO 4 + 10H 2 O⇔Na} 2 SO 4 * 10H 2 O
[0074] The sodium sulfate crystals produced have a high level of purity due to a number of upstream purification steps. Since only a small percentage of polyvalent metal ions in the solution precipitate on the electrolytic cell membrane, the absence of contamination allows electrolysis 30. Electrolysis of sodium sulphate produces sulfuric acid at the anode and sodium hydroxide at the cathode, which are the major essential depleting reagents for the process. This step eliminates the need to supply untreated sulfuric acid and sodium hydroxide to the process. For this type of process, the current density can fluctuate between 1-3 kA / m ² , while the corresponding voltage can fluctuate between 5 and 20 V at a constant bath temperature of 25 ° C. It is possible and the Na ₂ SO ₄ feed mass percentage can vary between 15 and 25%. The expected operating value should be a current density of 1 kA / m ² at a voltage of 10 V and a supplied Na ₂ SO ₄ mass percentage of about 18%. The electrode reaction is shown as follows:
Cathode:
2H ₂ O + 2e ⁻ ⇔ H ₂ + 2OH ⁻
2Na ⁺ + 2OH ⁻ ⇔ 2NaOH
anode:

SO ₄ ^2- + 2H ⁺ ⇔ H ₂ SO ₄
[0075] The mother liquor exiting the crystallizer was heated to a temperature of 80 to 100 ° C., adding a carbonate ion source _(CO ^{3 2-)} in aqueous solution. The carbonate ion source can be either a carbonate ionic compound such as sodium carbonate (Na ₂ CO ₃ ) or by bubbling CO ₂ gas to produce bicarbonate ions (HCO ₃ ⁻ ). The carbonate ion reacts with the lithium ion to produce lithium carbonate (Li ₂ CO ₃ ), which is slightly soluble in water31. It takes 30 minutes to 2 hours for the precipitation to stabilize, and the operation retention time is expected to be 1 hour. The precipitate is filtered, dried and sold as dry lithium carbonate 32.

[0076] The remaining aqueous solution is returned to the primary leaching sector for recycling to prevent sending lithium to water treatment.

Example I
[0077] All processes of the battery recycling method described in the examples below are performed continuously on a laboratory scale. The process includes shredding, grinding, sieving, electrolyte solvent extraction, leaching, precipitation (sulfides, hydroxides and carbonates), solvent extraction, electrowinning and crystallization. First, the battery is roughly shredded and the electrolyte solvent is recovered by evaporation. Next, the shredded solid is finely crushed and then sieved to magnetize and remove the plastic and iron, respectively, and leaching. Was added Na 2 _S to leachate to obtain a sulfide precipitate, then, obtain the hydroxide precipitate to raise the pH of the resulting leachate. The leachate is then contacted with an organic solvent. The organic solvent is then scrubbed, stripped and finally sent to an electrowinning cell. The pH of the aqueous solution is raised again to obtain nickel hydroxide. Then, the temperature is lowered to remove sodium, and then the temperature is raised to carry out carbonation precipitation.

[0078] First, about 150 g of a battery is shredded, immersed in a dimethyl carbonate solvent, and heated in a flask at 110 ° C. After filtration, the solvent is distilled off to recover the lithium salt (LiPF ₆ ). Next, the shredded battery is crushed into 0.1 to 2 mm parts and prepared for leaching.

[0079] Leachation requires 2 mol / L 98% concentrated sulfuric acid and 1.6 mL hydrogen peroxide per gram of metal powder. The leaching time can take up to 4 hours. The residue is washed with distilled water and filtered.

[0080] After filtration, the next step is sulfur precipitation for copper removal. 10 wt% sodium sulfide with respect to the metal powder is added to the leachate to precipitate copper sulfide (CuS). It is then washed and filtered. It took at least 30 minutes for the reaction to complete.

[0081] Next, after filtration, about 40 g of sodium hydroxide is added to the leachate to give a pH of 0-5.5 to give a precipitate of iron hydroxide and aluminum hydroxide. Due to the gel-like properties of iron hydroxide, the hydroxide precipitate was difficult to filter. This amount of NaOH was for 50 g of metal powder using ₂ mol / L H ₂ SO ₄ . The precipitate is washed and filtered.

The leachate is then contacted with a diluted organic solvent, which is a mixture of 10% by volume cyanex 272 and 90% by volume naphtha, at a 1: 1 organic leachate ratio. The aqueous phase is rich in nickel and lithium. The organic phase is scrubbed and stripped to allow recovery of cobalt and manganese. The organic phase is recycled to the initial operation of solvent extraction.

[0083] The pH of the cobalt and manganese concentrated solution is set to 3.5 and then transferred to an electrowinning cell to which a current density of about 200 A / m ² has been applied. After electrowinning at 50 ° C. for 1 hour, metallic cobalt is plated on the iron cathode and manganese dioxide is deposited on the lead anode.

[0084] After extraction with a solvent, the pH of the nickel- and lithium-rich aqueous phase is raised to 10.8 to obtain a nickel hydroxide precipitate. The precipitate is filtered and washed.
[0085] Adjust the pH of the aqueous phase to 8. Next, cool to 5 ° C. for 30 minutes in an ice bucket to extract sodium sulfate. This is filtered and washed.

[0086] Next, the aqueous phase is heated to 90 ° C., and sodium carbonate is added to cause a carbonation reaction to form lithium carbonate. The precipitate is filtered and washed. The reaction takes 1 hour.
The table below shows the efficiency of sediment analysis and manipulation:

Example II
[0088] The process of Example 1 was repeated, except that three additional operations were added: sieving, magnetization for iron removal, and reuse of the last aqueous solution containing a small amount of lithium.

[0089] Prior to leaching the metal powder, sieving was used to separate the metal powder from unwanted residues (plastic and metal parts). Next, small parts of iron are removed by magnetization. The addition of these two operations helped reduce both the amount of iron precipitation and the filtration time of the hydroxide.

[0090] By returning the last aqueous solution containing a small amount of lithium to the leaching process and recycling it, we will respect environmental standards and not only save water, but also recover the remaining uncarbonated lithium. Become.

Example III
[0091] In this embodiment, the leaching operation is repeated in order to further improve the efficiency of the leaching operation.

[0092] The efficiency of the leaching operation is improved by optimizing its parameters. A reducing agent such as 10 g / L aluminum (foil) or 4 g / L manganese dioxide is used to partially or completely substitute for hydrogen peroxide. The addition of MnO ₂ of 1.6 mL / g of _H 2 _{O 2} and 4g / L has appeared to be most efficient.

Although the present disclosure has been described with particular reference to the illustrated embodiments, it will be appreciated that a number of changes to them will be apparent to those skilled in the art. The disclosure is subject to further modification so that the application is within the scope of known or customary work within the art, can be applied to the important functions described above, and is subject to the scope of the appended claims. It is understood that it is intended to include any modification, use or adaptation of the invention, including deviations from the present disclosure.

Claims (25)

It ’s a way to recycle lithium-ion batteries.
a) A step of shredding a lithium-ion battery and immersing the residue in an organic solvent to safely discharge the battery to produce a shredded battery residue and a liquid containing an organic compound and lithium hexafluorophosphate;
b) A step of supplying shredded battery residue to a dryer to produce a gaseous organic phase and a dry battery residue;
c) A step of supplying a dry battery residue containing a magnetic battery residue and a non-magnetic battery residue to a magnetic separator to remove magnetic particles from the dry battery residue;
d) The step of grinding the non-magnetic battery residue to generate a particle size distribution that includes an upper limit range containing plastic and an intermediate and lower limit range of fine particles containing aluminum, copper, metal and graphite;
e) A step of mixing fine particles and an acid to produce a slurry and leaching the slurry to produce a leachate containing a metal sulfate and a non-leaching material;
f) The step of filtering the exudate to remove non-exudative material from the exudate;
g) A step of supplying a leachate to a sulfide precipitation tank to remove ionic copper impurities from the leachate;
h) A step of neutralizing the leachate to pH 3.5-5 to remove residual iron and aluminum from the leachate;
i) The step of mixing the leachate with an organic extraction solvent to produce an aqueous phase containing lithium and an organic phase containing cobalt, manganese, and nickel;
j) A step of crystallizing sodium sulfate from an aqueous phase containing lithium to produce a liquid containing lithium and sodium sulfate crystals;
k) A method comprising adding sodium carbonate to a solution and heating the sodium carbonate and the solution to form a lithium carbonate precipitate; and l) drying and recovering lithium carbonate. The method according to claim 1, wherein the organic solvent is an aliphatic carbonate. The method according to claim 1 or 2, wherein the temperature of the organic solvent is less than 40 ° C. The method according to any one of claims 1 to 3, wherein the lithium ion battery is shredded into a particle size of about 5 to 10 mm. The method of any one of claims 1 to 4, wherein the shredded battery residue is separated from the liquid by sieving or filtration. The method according to any one of claims 1 to 5, further comprising a step of evaporating the liquid in step a) with an evaporator to form a slurry and a condensate of a light organic substance. The method of claim 6, comprising the steps of separating dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) and ethylene carbonate (EC) from the condensate of light organic matter. The method according to claim 6, further comprising a step of recycling a condensate of a light organic substance as an organic solvent in step a). The invention according to any one of claims 6 to 8, wherein the slurry is burned at a temperature of about 500 ° C. to produce a combustion gas containing hydrofluoric acid (HF) and phosphorus pentoxide (P ₂ O ₅ ). Method. The HF was further removed by a dry _scrubber to neutralize the P 2 _{O 5} in the wet scrubber to form the sodium phosphate _(Na 3 PO _4), The method of claim 9. The method according to any one of claims 1 to 10, wherein the shredded battery residue is dried at a temperature between 200 and 300 ° C. The method according to any one of claims 1 to 11, wherein the non-magnetic battery residue is pulverized with a hammer mill or an impact crusher. The method according to any one of claims 1 to 12, further comprising the step of extracting aluminum and copper from the pulverized non-magnetic battery using an eddy current separator. 13. The method of claim 13, further separating aluminum and copper. The method according to any one of claims 1 to 14, wherein the fine particles are mixed with sulfuric acid and water to produce a metal oxide slurry having a solid concentration between 75 and 125 kg of solid per cubic meter of acid solution. The method according to any one of claims 1 to 15, further comprising a step of adding a reducing agent to the metal oxide slurry for leaching. 16. The method of claim 16, wherein the reducing agent is at least one of hydrogen peroxide (H ₂ O ₂ ), manganese oxide (MnO ₂ ), aluminum (Al) and a combination thereof. The method according to any one of claims 1 to 17, further comprising the step of filtering graphite from the leachate and purifying it in a furnace. 18. The method of claim 18, wherein the furnace is operating at a temperature of about 200-800 ° C. The method according to any one of claims 1 to 19, further comprising a step of precipitating ionic copper impurities by precipitation using sulfide ions. The method according to any one of claims 1 to 20, further comprising a step of mixing the leachate and the organic extraction solvent in the diluent in step j). The method according to any one of claims 1 to 21, further comprising a step of scrubbing and stripping the organic phase from step i) to extract cobalt and manganese. 22. The method of claim 22, wherein cobalt and manganese are separated by electrowinning. The method according to any one of claims 1 to 23, further comprising a step of raising the pH of the aqueous phase to a pH between 10 and 12 to precipitate nickel from the aqueous phase. The method according to any one of claims 1 to 24, further comprising the step of electrolyzing sodium sulfate crystals to produce sulfuric acid and sodium hydroxide.

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